Veterans Affairs Secretary Eric Shinseki on Thursday ordered a nationwide health care access review as frustration continued to mount over VA’s response to allegations of care delays leading to patient deaths.

The review, to be conducted over the next few weeks, will include meetings with all VA schedulers to ensure they are following proper protocol and record keeping on health care appointments.

In a statement, department officials said the review will “ensure a full understanding of VA’s policy and continued integrity in managing patient access to care.”

“Our most important mission is to make sure veterans know VA is here to care for them and provide the high-quality care and benefits they have earned and deserve.”

For critics, the move comes too late. Earlier in the week, the American Legion called for the resignation of Shinseki and two of his top deputies, citing a pattern of “poor oversight” and “failed leadership.”

“It’s not something we do lightly,” said Daniel Dellinger, the Legion’s national commander. “But we do so ... because it is our responsibility as advocate for the men and women who have worn this nation’s uniform. There needs to be a change, and that change needs to occur at the top.”

At least six Republican lawmakers also have called for Shinseki to step down, and Senate Minority Leader Mitch McConnell, R-Ky., said a change in leadership “might be a good thing” for VA.

On Thursday, visibly irritated members of the House Veterans’ Affairs Committee subpoenaed all correspondence from top VA leaders regarding the alleged secret waiting list at the heart of the Phoenix VA health system scandal.

Last month, lawmakers highlighted rumors that officials were keeping two lists of care appointments: one showing timely responses to veterans’ requests for care, and an accurate, off-the-books list showing major delays in seeing physicians.

Whistle-blowers in the system have claimed as many as 40 patients died waiting for care. Three Phoenix VA officials have been put on administrative leave pending a full investigation, but have maintained that no secret list existed.

VA officials disputed that, but said they’ll work with the committee to comply with the subpoena.

Shinseki has maintained that any response to the Phoenix allegations will not come until after a full VA inspector general review of the problems. No timetable has been announced for that investigation.

During the week of May 5, news reports uncovered allegations of similar care delay problems in Colorado and Texas. Last month, a VA review found that delays in cancer treatment consultations caused by administrative confusion may have played a role in the deaths of 23 veterans nationwide and compromised the health of 53 others.

Leaders of Veterans of Foreign Wars and Disabled American Veterans have said they don’t think Shinseki should resign, but have expressed serious concerns about how patients are being treated at VA clinics and hospitals.

Officials from AMVETS on May 7 called for Shinseki “to publicly shed the misperceptions of failed leadership and accountability,” saying he has failed to keep the public updated on the investigation. But they also said forcing Shinseki to resign will not solve VA’s most troubling challenges.

Leaders from Iraq and Afghanistan Veterans of America have called for President Obama to publicly address the issue, saying the concerns over the department have grown too large to ignore.

Meanwhile, the Senate Veterans’ Affairs Committee announced Thursday that Shinseki will testify May 15 before the committee on the state of VA health care.

Sen. Bernie Sanders, the Vermont Independent who chairs the committee, said Shinseki and others have been called to discuss “what the VA health care system does well and how it can improve care for veterans.”

Sanders, an ardent supporter of VA, said in an April hearing that he is waiting for the results of a VA Inspector General’s investigation into the Phoenix allegations before passing judgment.

“Some 200,000 veterans get care every single day and independent studies consistently show that VA provides, in general, excellent care to our veterans,” Sanders said.

In a statement, Sanders said the hearing scheduled for next week will take a “broader look at the overall VA health care system.”

“In a system as large and bureaucratic as VA, it is imperative that we uncover the problems that exist in the system and address them boldly. The veterans of our country deserve the best-quality care that we can provide and I intend to do my best to make sure that happens,” Sanders said.

Shinseki told Military Times on Wednesday that VA will mete out “swift and appropriate” punishment for any employees who may have been involved with medical appointment delays and subsequent coverups at VA hospitals in Arizona and Colorado.